The present invention relates generally to automatic access control. More particularly the invention relates to an access control device according to the preamble of claim 1, a data communication system according to the preamble of claim 5 and a method according to the preamble of claim 11. The invention also relates to a computer readable medium according to claim 16.
In modern buildings, especially in business premises, electronic access control (EAC) systems are often used to control entries to and exits from various facilities. Here, the door locks are normally remote controlled from a central node based on credential data defining which subjects who are authorized to enter a certain area during a given interval of time. The credential data, in turn, may be embodied in a key fob, a smartcard, a proximity card or other appropriate carrier, e.g. a subscriber identity module (SIM) card of a mobile telephone or a personal digital assistant (PDA).
US 2007/0222542 describes a solution for transferring electromagnetic energy wirelessly to a first resonator structure from an external power supply, which includes a second resonator structure. Thus, it is rendered possible to charge for example laptops and cell-phones in a convenient manner, i.e. without the need for matching connectors between the charger and the device being charged.